When foundations settle, cracks in foundation walls can result. Most foundation walls in Alabama are constructed of concrete masonry or solid concrete. Some walls are not reinforced and others are sometimes lightly reinforced. Seldom do walls contain horizontal reinforcement in the form of rebar in concrete or joint steel in masonry. All concrete materials shrink in volume soon after construction due to loss of water upon drying/curing. As the concrete materials shrink, there is a corresponding dimension change that takes place. The foundation wall is typically bonded to the buried concrete footing so the shrinkage is well restrained along the bottom. At the top, the fairly light wood frame superstructure doesn’t provide much restraint. As such, vertical cracks will often form near the centers of long walls which are widest at the top and which narrow to hairline size at the base. These are called shrinkage cracks and they are usually structurally unimportant. (Note: another form of vertical cracking is caused by sweeping, inward bowing of basement walls which can be a problem/concern).